Loddon River system (including Tullaroop, Serpentine and Pyramid creeks)

The Loddon River flows from the Great Dividing Range in the south to the River Murray in the north. Tullaroop Creek is the main tributary in the upper Loddon River system. The middle section of the Loddon River is characterised by many distributary streams and anabranches that carry water away from the river onto the floodplain. The lower Loddon River is joined by Pyramid Creek at Kerang, at which point the Loddon becomes part of the River Murray floodplain.

The Loddon River continues to be an important place for Traditional Owners and their Nations. The Registered Aboriginal Party (RAP) in the region is the Dja Dja Wurrung Clans Aboriginal Corporation. Representatives from Dja Dja Wurrung, Barapa Barapa and Wamba Wemba Traditional Owners were engaged during the preparation of the Loddon system seasonal watering proposals.

System map

Grey river reaches have been included for context. The numbered reaches indicate where relevant environmental flow studies have been undertaken. Coloured reaches can receive environmental water.

Environmental watering objectives in the Loddon River

Protect and increase populations of native fish by providing flows for them to move upstream and downstream Maintain the water quality and the variety of aquatic habitats

Maintain river red gum, tea tree and lignum and provide opportunities for new plants to germinate and grow Limit encroachment of emergent macrophytes and allow in-stream vegetation to spread to channel margins Establish and maintain a variety of vegetation types

Create opportunities for platypus to disperse throughout the system Maintain access to foraging habitat Provide opportunities for successful breeding and recruitment

Environmental values

The Loddon River system supports platypus, frogs, turtles and fish. Streamside vegetation varies in condition depending on the recent water regime, the extent of clearing and historic and current land management practices. Those areas remaining relatively intact support a variety of woodland birds and other native animals. Important plant species across the system include cane grass, tangled lignum, black box and river red gum.

Although fish populations in the Loddon system are affected by the many barriers caused by weirs and reservoirs, a large range of species are still found through the catchment. Native fish are most-abundant and diverse in the upper catchment. River blackfish are found in Serpentine Creek and rare Murray-Darling rainbow fish are found in the middle sections of the Loddon River. Pyramid Creek supports large-bodied fish (such as golden perch, Murray cod and silver perch) and is an important corridor for fish migration between the Loddon and Murray systems. Engineering works to provide fish passage at the Chute, Box Creek regulator and Kerang Weir in recent years have been important in reopening these migration routes.

Social and economic values

The Loddon River supplies the Loddon Valley Irrigation Area and is essential for the area's prosperity. In the highly productive irrigation areas in the lower catchment, the main land uses are dairying, pasture and irrigated horticulture. Mixed farming and cereal growing dominate the middle and upper catchment.

Storages and weir pools that form part of the irrigation network are used for recreational activities, particularly during the drier months when river levels are low. The river is an important recreational hub with locals and visitors using it for camping, hunting, waterskiing, canoeing, boating, and for walking and cycling along its banks. Murray cod and golden perch are stocked in the Loddon River and are important recreational fishing species. Bridgewater on Loddon hosts regional and national waterskiing and triathlon competitions.

Conditions 2018

Rainfall patterns in the Loddon catchment varied throughout 2017–18. There was a relatively dry period in September/October 2017 and a short-lived wet period in November 2017 to January 2018. However, the late spring/ early summer rain did not deliver high inflows because the rainfall was sporadic and the catchment was fairly dry. Late summer and autumn were particularly dry and environmental flows were required to maintain flows in the reaches downstream of Loddon Weir.

Most flow recommendations for summer low flows and freshes in the reaches upstream of Loddon Weir were exceeded because large volumes of irrigation water were delivered. In the priority reach, between Loddon Weir and Kerang Weir, all environmental flow components were delivered except for those which rely on unregulated flows or storages spilling.

In 2017, winter low flows and a spring fresh were delivered to Serpentine Creek for the first time. The releases helped managers understand the rate at which managed flows move through Serpentine Creek and into Pennyroyal and Bannacher creeks at the end of the system. The observations will help environmental planning in future years to support objectives for waterbirds, vegetation and native fish while limiting impacts on landholders.

Pyramid Creek and the Loddon River have benefited from actions implemented in the first three years of the North Central CMA's Native Fish Recovery Plan – Gunbower and Lower Loddon. Reinstatement of habitat, fish passage and an improved flow regime have significantly improved conditions for fish, particularly Murray cod and golden perch. Two environmental flows were provided to Pyramid Creek during 2017–18 to support the plan. The first was delivered in spring and involved coordinated releases through Pyramid Creek and reach 4 of the Loddon River, to attract fish from the lower Loddon and River Murray to move through Kerang Weir and the Box Creek regulator fishway at Kow Swamp. The second was delivered at the end of the irrigation season in mid-May to control the rate of drawdown in Pyramid Creek, to prevent fish becoming stranded when the irrigation system is drained. The environmental flows in Pyramid Creek could not be achieved without the cooperation and expertise of the storage manager, Goulburn-Murray Water.

Scope of environmental watering

Table 1 Potential environmental watering actions and objectives for the Loddon River system

Potential environmental watering

Environmental
objectives

Loddon River (reach
1)

Summer/autumn freshes (up to 4 freshes of 35–80 ML/day for 1–3 days in December– May)

Provide a cue for fish movement so they access alternate habitats

Wash organic matter into the stream to drive the aquatic food webs

Mix and re-oxygenate pools and dilute concentrated salt

Inundate lower banks to wet the soil and promote the establishment, growth and survival of sedges and reeds

Winter/spring freshes (1–2 freshes of 400–700 ML/day for 1–5 days in July–October)

Autumn high flow (1 high flow of 700–900 ML/ day for 10 days in March-May)

Maintain connectivity between habitats and improve water quality

Trigger and facilitate the movement of juvenile fish

Provide recruitment opportunities for Murray cod and other native fish species

1 Due to potential inundation of private land, environmental flows above 450 ML per day in reach 4 will not be provided without agreement of potentially affected landholders.

2 Flows in Serpentine Creek will be shepherded through the system and allowed to run down in Pennyroyal Creek and Nine Mile Creek with the

agreement of landholders.

Risk management

In preparing its seasonal watering proposal, North Central
CMA considered and assessed the risks of environmental
watering and identified mitigation strategies. Program
partners continually reassess risks and mitigation actions
throughout the water year.

Engagement

Table 2 shows the partners and stakeholder organisations with which North Central CMA engaged when preparing their seasonal watering proposals.

Seasonal watering proposals are informed by longer-term regional catchment strategies, regional waterway strategies, environmental flow studies, water management plans and other studies. These incorporate a range of environmental, cultural, social and economic perspectives and longerterm integrated catchment and waterway management objectives. For further details, refer to the North Central Regional Catchment Strategy and North Central Waterway Strategy.